One-step hydrothermal synthesis of S-defect-controlled ZnIn2S4 microflowers with improved kinetics p

• 作 者: Xuedong Jing Na Lu Jindou Huang Peng Zhang Zhenyi Zhang
• 机 构: Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission
• 出 处: 能源化学
• 发表日期: 2021年7期
• 关键词: Photocatalysis H2 evolution Defect engineering Charge-carrier kinetics Hydrother

Engineering lattice defects in two-dimensional (2D) sulfide semiconductors has been accepted as an effective strategy to enhance the efficiency of the solar-to-fuels conversion.Although many researches have proven the lattice defect-mediated photocatalytic activity of ZnIn2S4,the artificial control of S-defects for optimizing the charge-carrier kinetics process in ZnIn2S4 has long been a challenging task.Herein,we report a facile one-step method to modulate the lattice S-content of ZnIn2S4 microflowers (MFs) only through adjusting the used amount of S-precursor in the hydrothermal solution that contains the metal precursors with a fixed Zn/In stoichiometric ratio at 1∶2.We also demonstrated that the S-vacancies at the In facets were the main type of lattice defects in the formed ZnIn2S4 MFs,which could enhance both the separation and migration processes of the photoinduced charge-carriers due to the existence of discrete defect energy-levels (DELs) and the reduced effective mass of eIectrons,as evidenced by the first-principles calculations and the electron spectra analyses.The ZnIn2S4 MFs with the optimal content of S-vacancy obtained by a hydrothermal treatment of the precursors with the Zn/In/S stoichiometric ratio of 1:2:8 possessed the long-lived photoinduced electron (～94.64 ns) for contributing to the photo-physical and-chemical processes.Thus,upon visible light irradiation,the H2-evolution rate of this sample reached ～ 2.40 mmol h-1 g-1 with an apparent quantum efficiency of ～ 0.16％ at 420 nm even though only using 5 mg of photocatalysts without any cocatalysts.